Semiconductor substrate cleaning system

ABSTRACT

A modular semiconductor substrate cleaning system is provided that processes vertically oriented semiconductor substrates. The system features a plurality of cleaning modules that may include a megasonic tank-type cleaner followed by a scrubber. An input module may receive a horizontally oriented substrate and rotate the substrate to a vertical orientation, and an output module may receive a vertically oriented substrate and rotate the substrate to a horizontal orientation. Each of the modules (input, cleaning and output) has a substrate support and may be positioned such that the substrate supports of adjacent modules are equally spaced. The modules are coupled by an overhead transfer mechanism having a plurality of substrate handlers spaced the same distance (X) as the substrate supports of the modules therebelow. The transfer mechanism indexes forward and backward the distance X to simultaneously transport semiconductor substrates through the cleaning system, lifting and lowering substrates from the desired modules wafer rotation/orientation sensors, an input module cart for transporting wafers between a substrate handler of a previous tool (such as a semiconductor substrate polisher) and a substrate handler of the cleaning system are also included.

[0001] The present application is a division of U.S. patent applicationSer. No. 09/558,815, filed Apr. 26, 2000, which claims priority fromU.S. Provisional Patent Application Serial No. 60/131,124 filed Apr. 27,1999 and No. 60/143,230 filed Jul. 10, 1999. All of these patentapplications are incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

[0002] Currently available semiconductor substrate cleaning equipmentsuffers from high cost per unit substrate cleaned, unreliable removal oflarge flat particles, and of particles located along the beveled edge ofa semiconductor substrate, lack of scalability and inability to easilyadapt to various processing sequences, or to changes (e.g., increases)in semiconductor substrate size. Among the many factors that contributeto substrate cleaning costs, the capital cost of substrate handlerswhich move semiconductor substrates between various locations presents asignificant expense. Another significant expense arises becausesemiconductor substrate cleaning processes are performed within a cleanroom environment. The larger the area occupied by the cleaning system(i.e., the larger the footprint) the more expensive the cleaning systemis to operate, due to the high cost of clean room area.

[0003] Unreliable cleaning, however, increases cleaning costs more thanany other factor. As semiconductor substrates increase in size, failuresbecome more expensive, and as devices formed on semiconductor substratesdecrease in size, particles are more likely to cause failures.

[0004] Accordingly, improvements are needed in the field ofsemiconductor substrate cleaning.

SUMMARY OF THE INVENTION

[0005] An inventive semiconductor substrate cleaning system comprises aplurality of cleaning modules, each module has a substrate support forsupporting a vertically oriented semiconductor substrate during acleaning process, and each module is positioned such that the substratesupports thereof are spaced a fixed distance X. An input modulepositioned adjacent a first end module of the plurality of cleaningmodules has a substrate support positioned a distance X from thesubstrate support of the first end module, and an output modulepositioned adjacent a second end module of the plurality of cleaningmodules has a substrate support positioned the distance X from thesubstrate support of the second end module. A semiconductor substratetransfer mechanism having a plurality of substrate handlers spaced thedistance X is movably coupled above the plurality of cleaning modulesand above the input and output modules so as to move forward andbackward the distance X, thereby simultaneously carrying semiconductorsubstrates between adjacent ones of the input module, the cleaningmodules and the output module.

[0006] For cases where the substrates are not loaded vertically into theinput module and/or are not unloaded vertically from the output module,the input and/or output modules may respectively include a mechanism forreceiving a semiconductor substrate in a horizontal orientation and forrotating the semiconductor substrate to a vertical orientation and amechanism for receiving a semiconductor substrate in a verticalorientation and for rotating the semiconductor substrate to a horizontalorientation. Likewise, to facilitate wafer handling, the input modulemay orient the substrate to place the substrate's flat in a knownposition (i.e., flat finding) such that the wafer handler will notcontact the flat. In steady state operation, semiconductor substratesmay be loaded to and unloaded from the system, are appropriatelyoriented horizontally or vertically and/or have their flatsappropriately positioned while other substrates are being cleaned.System productivity therefore may be enhanced as the system need notidle during the time required for substrate load/unload and orientoperations.

[0007] After semiconductor substrates are loaded to and unloaded fromthe system via the input module and the output module, the overheadtransfer mechanism lowers the wafer handlers. In one aspect the waferhandlers are simultaneously lowered into the input module and thevarious cleaning modules to pick up or “grip” semiconductor substratescontained therein. Thereafter, by simply raising, indexing forward thedistance X and lowering, the transfer mechanism simultaneously transfersa plurality of single substrate batches from one module to the next. Thetransfer mechanism ungrips the substrates, raises and returns to thehome position while substrates are loaded/unloaded and oriented in theinput and output modules. This process repeats until each substratereceives the desired processing and is unloaded. In this aspect, thesimplicity of the simultaneous substrate transfer mechanism providesaccurate yet cost effective substrate transfer.

[0008] The entirely vertical orientation of the cleaning modulesrequires minimal footprint, and enables the inventive cleaning system tobe easily scaled. To accommodate changes in substrate size the substratesupports and wafer handlers may be adjustable. Thus, few alterations arerequired for change-over between cleaning substrates of differing size.

[0009] Other inventive aspects of the cleaning system comprise, in oneaspect the use of a megasonic tank cleaner, followed by a scrubber, andin another aspect the design of a cleaning system which does not employa scrubber.

[0010] Further features and advantages of the present invention willbecome more fully apparent from the following detailed description ofthe preferred embodiments, the appended claims and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIGS. 1A-F are schematic side elevational views of an inventivecleaning system;

[0012]FIG. 2 is a timing diagram useful in describing the operation ofthe inventive cleaning system of FIGS. 1A-G;

[0013] FIGS. 3A-C are side perspective views of an inventive interfacemodule;

[0014]FIG. 4 is a perspective view showing the inventive interfacemodule of FIGS. 3A-C coupled between an existing wafer handler and acleaning module;

[0015]FIG. 5A is a side elevational view of a roller employed within theinventive interface module of FIGS. 3A-C;

[0016] FIGS. 5B-C are front plan views of the cart employed within theinterface module of FIGS. 3A-C, useful in describing wafer orientation;

[0017] FIGS. 6A-B are front plan views of the cart employed within theinterface module of FIGS. 3A-C, useful in describing an apparatusgenerally useful for wafer orientation and rotation monitoring;

[0018] FIGS. 7A-C are a side view and two front views, respectively, ofa through-beam sensor for orienting a wafer;

[0019]FIG. 8 is a schematic front elevational view of a substratesupport that is particularly advantageous for rotating flattedsubstrates;

[0020]FIGS. 9A and 9B are a front elevational view of a first embodimentof a first aspect of an inventive Marangoni drying module 81 a showingthe exterior thereof, respectively showing a substrate receivingposition and a substrate guiding position as described below;

[0021]FIG. 9C is a front sectional view of the Marangoni drying moduleof FIG. 1B showing the interior thereof;

[0022] FIGS. 9D-F are sequential side sectional views of the Marangonidrying module of FIGS. 9A, 9B, and 9C, useful in describing theoperation thereof;

[0023]FIG. 10A is a front elevational view of a second embodiment of aMarangoni drying module; and

[0024] FIGS. 10B-D are sequential side sectional views of the Marangonidrying module of FIG. 10A, useful in describing increased throughputthereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] FIGS. 1A-F are schematic side elevational views of an aspect ofan inventive cleaning system 11 having an input module and an outputmodule that rotate a substrate between horizontal and verticalpositions. The inventive cleaning system 11 comprises a load module 13,a plurality of cleaning modules configured to support a semiconductorsubstrate in a vertical orientation, specifically a megasonic cleaner15, a first scrubber 17, a second scrubber 19, and a spin-rinse-dryer21; and an unload module 23. The megasonic cleaner 15 may be configuredas described in U.S. patent application Ser. No. 09/191,057, filed Nov.11, 1998 (AMAT No. 2909/CMP/RKK). The first scrubber 17 and the secondscrubber 19 may be configured as described in U.S. patent applicationSer. No. 09/113,447, filed Jul. 10, 1998 (AMAT No. 2401/CMP/RKK). Thespin-rinse-dryer 21 may be configured as described in U.S. patentapplication Ser. No. 09/544,660, filed Apr. 6, 2000 (AMAT No.3437/CMP/RKK) and the substrate transfer mechanism described below maybe configured as described in U.S. patent application Ser. No.09/300,562, filed Apr. 27, 1999 (AMAT No. 3375/CMP/RKK). The entiredisclosure of each of the above identified applications is incorporatedherein by this reference. It will be apparent that the apparatusesdisclosed in the applications incorporated above are merely exemplaryand other apparatuses may also be employed.

[0026] Each of the modules 13-23 has a substrate support 25 a-f,respectively, for supporting a semiconductor substrate in a verticalorientation. It will be understood that the substrate supports 25 b-emay be configured like the substrate supports described in thepreviously incorporated U.S. patent applications. The exemplary loadmodule 13 is configured to receive a horizontally oriented semiconductorsubstrate and to rotate the semiconductor substrate to a verticalorientation. Similarly, the exemplary unload module 23 is configured toreceive a vertically oriented semiconductor substrate and to rotate thesemiconductor substrate to a horizontal orientation. To perform suchsubstrate reorientation the substrate supports 25 a, 25 f, of the loadmodule 13 and the unload module 23 are preferably operatively coupled toa rotation mechanism 27 a, 27 b, respectively, such as a motorizedhinge.

[0027] Each of the modules may include an alignment and latchingmechanism 29 a-e for securing to adjacent modules so as to hold themodules in a predetermined position relative to each other. When in thispredetermined position the substrate supports 25 a-f may be equallyspaced by a distance X (FIG. 1A). To facilitate this equal spacing, thecleaning modules 15-21 each have a length which is less than a distanceX. Accordingly, the cleaning system 11 may be easily reconfigured toperform a number of different cleaning sequences. By unlatching thelatching mechanisms 29 a-f a module may be easily removed, replaced orreconfigured (i.e., the modules are “removably coupled”).

[0028] The latching mechanisms 29 a-e are adjustable to allow a cleaningmodule 15-21 to be either coupled closely adjacent a load/unload module13, 23, or to allow a cleaning module 15-21 to be coupled to an adjacentcleaning module 15-21 in a spaced relationship such that the overalldistance D (FIG. 1A) between the wafer position in the first cleaningmodule and the wafer position in the next adjacent cleaning module isequal to a fixed distance (FIG. 1A). In this manner, each of thesubstrate supports 25 a-e may be equally spaced the distance X (FIG. 1A)from the adjacent substrate supports 25 on either side thereof, providedall modules have an overall width W_(n) less than or equal to thedistance X. Further, although the wafer position within any module neednot be centered between the front and back face of the module, thedistance between the wafer and the front face of the module and thedistance between the wafer and the back face of the module may be lessthan or equal to one-half of X (the distance between adjacent wafersupports) so as to preserve configurability.

[0029] A substrate transfer mechanism 31 having a plurality of substratehandlers 33 a-e is operatively coupled above the plurality of modules13-23. In this example, the substrate handlers 33 a-e are spaced by thedistance X (FIG. 1A) and are equal in number to the number (n) ofmodules 13-23 in a given cleaning system configuration, minus one (n−1).The substrate transfer mechanism 31 is coupled so as to move thedistance X (FIG. 1A), from a “load” position wherein the first substratehandler 33 a is positioned above the load module 13, to an “unload”position, wherein the last substrate handler 33 e is positioned abovethe unload module 23. The exemplary substrate handlers 33 a-e arefixedly coupled horizontally, and thus move horizontally as a unit. Theexemplary substrate handlers 33 a-e are also fixedly coupled vertically,and the substrate transfer mechanism 31 is movably coupled so as to liftand lower a distance Y (FIG. 1B) from a position wherein each substratehandler 33 a-e operatively couples one of the substrate supports 25 a-f(so as to place or extract a wafer thereon or therefrom), to a positionwherein the lowest edge of each substrate handler 33 is at an elevationabove the highest edge of each module 13-23. Thus the substrate handler33 also moves vertically as a unit, between a “hand-off” position(wherein the substrate handlers 33 a-e operatively couple the substratesupports 25 a-f) as shown in FIGS. 1A and 1D, and a “transport” position(wherein the substrate handlers 33 a-e are elevated above the modules)as shown in FIGS. 1B, 1C, 1E and 1F. The substrate handlers 33 a-e maybe removably coupled to the substrate transfer mechanism 31 (e.g., via alatch, etc.) so that each substrate handler may be easily removed orreplaced, allowing the cleaning system to be easily reconfigured.

[0030] The operation of the inventive cleaning system 11 is describedwith reference to the timing diagram of FIG. 2 and with reference to thesequential views of FIGS. 1A-D, which show the movement of the substratetransfer mechanism 31 as it loads/hands off a plurality of singlesubstrate batches, transports the plurality of single substrate batches,and unloads/hands off the plurality of single substrate batches.

[0031]FIG. 1A shows the cleaning system 11 during steady stateprocessing in the load/hand-off position. The substrate handlers 33 a-eoperatively couple the substrate supports 25 a-e of the load module 13,the megasonic cleaner 15, the first scrubber 17, the second scrubber 19and the spin-rinse-dryer 21 respectively, so as to contact the edges ofthe semiconductor substrates S₁₋₅ positioned thereon.

[0032] After gripping the substrates S₁₋₅, the substrate transfermechanism 31 elevates the distance Y (FIG. 1B), to the transportposition shown in FIG. 1B. As the substrate transfer mechanism 31elevates, the substrate handlers 33 a-e lift the semiconductorsubstrates S₁₋₅ from the substrate supports 25 a-e, respectively. Whilein the transport position the substrate transfer mechanism 31 indexeshorizontally the distance X (FIG. 1A), from the load position whereinthe first substrate handler 33 a is above the load module 13, and thelast substrate handler 33 e is above the spin-rinse-dryer 21, to theunload position wherein the first substrate handler 33 a is above themegasonic cleaner 15, and the last substrate handler 33 e is above theunload module 23, as shown in FIG. 1C. After indexing the distance X tothe unload position the substrate handlers 33 a-e are respectivelypositioned above the substrate supports 25 b-f of the megasonic cleaner15, the first scrubber 17, the second scrubber 19, the spin-rinse-dryer21 and the unload module 23.

[0033] The substrate transfer mechanism 31 then lowers the distance Y tothe unload/handoff position shown in FIG. 1D, wherein the substratehandlers 33 a-e operatively couple the substrate supports 25 b-f,respectively. The substrate handlers 33 a-e ungrip the substrates S₁₋₅,placing the substrates S₁₋₅ on the substrate supports 25 b-f. Thesubstrates S₁₋₅ are processed within the megasonic cleaner 15, the firstscrubber 17, the second scrubber 19 and the spin-rinse-dryer 21,respectively, while the substrate transfer mechanism 31 elevates thedistance Y (FIG. 1B) to the transport position as shown in FIG. 1E. Thesemiconductor substrates S₁₋₅ continue processing within the cleaningmodules 15-21 while the substrate transfer mechanism 31 (still in thetransport position) indexes the distance X (FIG. 1A) from the unloadposition to the load position shown in FIG. 1F.

[0034] While the substrate transfer mechanism 31 is indexing from theunload position to the load position, the rotation mechanism 27 b withinthe exemplary unload module 23, rotates the substrate support 25 f andthe semiconductor substrate S₅ positioned thereon, from a verticalorientation to a horizontal orientation and may optionally perform flatfinding to place the semiconductor substrate S₅'s flat in a knownposition. Also while the substrate transfer mechanism 31 is indexingfrom the unload position to the load position a horizontally orientedsemiconductor substrate S₆ is loaded into the load module 13 (e.g., viaa substrate handler not shown). The rotation mechanism 27 a within theload module 13 then rotates the substrate support 25 a and thesemiconductor substrate S₆ positioned thereon, from a horizontalorientation to a vertical orientation.

[0035] Alternatively, the substrate handlers 33 a-e may have endeffectors configured to grasp flatted wafers regardless of theirorientation, such as those disclosed in U.S. patent application Ser. No.09/559,889, filed Apr. 26, 2000 (AMAT No. 3554) the entire disclosure ofwhich is incorporated herein by this reference. Specifically, thatapplication describes two opposing end effectors each having two pairsof opposing surfaces for contacting the edge of a substrate. Thus, theend effectors are designed to contact a substrate at four points alongits edges. If a substrate is oriented such that a flatted region of thesubstrate is adjacent one of the contacting points (e.g., one of thepairs of opposing surfaces) the substrate may still be stabily supportedby the remaining three contact points. Each of the contact points may beradiused to follow the circumference of the substrate to thus ensurethat contact occurs only along the substrates edges.

[0036] The load module may optionally perform flat finding to place thesemiconductor substrate S₆'s flat in a known position where it will notbe contacted by the substrate transfer mechanism 31. Each cleaningmodule may comprise a flat finding mechanism such that a substrate'sflat is in a known position when contacted by the substrate transfermechanism 31. For instance, the flat finder described in U.S. patentapplication Ser. No. 09/544,660, filed Apr. 6, 2000 (AMAT No.3437/CMP/RKK) may be employed in the spin-rinse-dryer 21. A flat finderwhich may be used in the scrubbers 15, 17 and the megasonic tank 83 isdescribed below with reference to FIGS. 6A-B and 7A-B.

[0037] Alternatively, rather than employing flat finding, if thesubstrate enters a module in a known position, a programmed controllercan return the substrate to that position because the substrate supportsof the various modules rotate the substrate at a known rate, and therotation time can be selected so as to return the substrate to theknown, “flat found” position provided the substrate supports aredesigned (e.g. with roughened surfaces) so as to prevent substrateslipping. After processing within the cleaning modules 15-21 iscomplete, the substrate transfer mechanism 31 lowers the distance X(FIG. 1A) to the load/handoff position as shown in FIG. 1A. Thereafterthe sequence repeats, with the semiconductor substrate S₅ being unloadedfrom the unload module 23 (e.g., manually or by a substrate handler notshown) while the substrate transfer mechanism 31 is in the positionshown in FIG. 1A or FIG. 1B.

[0038] The cleaning system 11 comprises a controller C operativelycoupled to the substrate transfer mechanism 31. The controller C maycomprise a program for moving the transfer mechanism 31 from a load/handoff position in which one of the substrate handlers 33 a-e operativelycouples the substrate support 25 a of the load module 13 and theremaining wafer handlers each operatively couple the substrate supportof one of the cleaning modules 15-21, to a transfer position in whichthe substrate handlers 33 a-e are above the input module 13 and abovethe cleaning modules 15-21. The controller C is also programmed to shiftthe transfer mechanism 31 a distance X (FIG. 1A) such that eachsubstrate handler 33 a-e is positioned above the substrate supports of acleaning module 15-21 or of the unload module 23, and to lower thetransfer mechanism 31 to an unload/handoff position in which thesubstrate handlers 33 e operatively couple the substrate support 25 f ofthe unload module 23 and the remaining substrate handlers 33 a-d eachoperatively couple a substrate support of one of the cleaning modules15-21. Thus, the controller C may be programmed such that a plurality ofsubstrates are simultaneously stepped through the plurality of singlesubstrate load, clean and unload modules. Further, the controller C maybe coupled to the rotation mechanism 27 a of the load module 13 and tothe rotation mechanism 27 b of the unload module 23. The controllerprogram may change semiconductor substrate orientation and mayoptionally perform flat finding at the load and the unload modules 13and 23, while the substrate transfer mechanism 31 is in the transferposition, and/or may return substrates to a known flat found position aspreviously described.

[0039] As described above, and as best understood with reference to thetiming diagram of FIG. 2, substrate load/unload, orient and the optionalflat finding may occur while substrates are being processed within thecleaning modules. Thus, in the exemplary system of FIGS. 1A-F, theoverall cleaning time of each semiconductor substrate is equal to thecycles of transport and six cycles of processing, and the cleaningmodules operate continuously except during substrate transport. In thisexample, the cleaning modules 15-21 do not idle while substrates areloaded, unloaded, oriented or flats are found. Therefore during steadystate processing, six semiconductor substrates exit the inventivecleaning system during the overall cleaning time of a singlesemiconductor substrate (i.e., during six cycles of transport andprocessing), and the steady state throughput of the inventive cleaningsystem equals the inverse of the sum of the transfer time and theprocess time.

[0040] The inventive cleaning system, may be configured formegasonically cleaning a substrate within a tank of fluid, followed byscrubbing the substrate. Such a configuration may more effectivelyremove large flat particles and particles located on the beveled edge ofa semiconductor substrate, than do conventional systems which employonly megasonics or only scrubbers.

[0041] The input module 13 may comprise an interface module 41 as shownin FIGS. 3A-C, if substrates are to be received in a verticalorientation. FIGS. 3A-C are side perspective views of the inventiveinterface module 41. The interface module 41 comprises a track 43 whichis coupled to a motor by a timing belt (both not shown) and a substratecart 45 which is moveably coupled to the track 43. The track 43 may bepositioned on a slope in the Z direction (represented by the angle “β”in FIG. 3B), by coupling one end of the track 43 at a higher elevationthan the other end of the track 43 (as shown). Similarly, the track 43may be slanted in the X direction (represented by the angle “α” in FIG.3C). In this manner the interface module 41 may be easily positioned ina “3D” manner to receive a vertically oriented wafer from a waferhandler (not shown) and to carry the wafer to a position where it may beloaded into the cleaning module 15 of the cleaning system 11. Thus, theinterface module 41 is easily adjustable to facilitate substratetransfer between wafer handlers which may be positioned at variousangles.

[0042] For example, as shown in FIG. 4, a wafer handler 48 travels alonga track 50. The wafer handler 48 therefore may reach as far as alocation A. The cleaning system 11's substrate transfer mechanism 31requires a substrate S to be positioned at a location B in order to begripped by the substrate handler 33 a thereof. Accordingly, theinterface module 41 is configured to extend between locations A and B,which have differing elevations (angle B) and differing locations in theX direction (angle α). The track 43 extends between locations A and B,and the substrate cart 45 is coupled to the track 43 with an angle thatplaces the substrate cart 45 in line with wafer handler 48 when thesubstrate cart 45 is in a transfer position (at location A) and in linewith substrate transfer mechanism 31 when the substrate cart 45 is in aload position (at location B). In order to allow the substrate cart 45to be easily positionable the substrate cart 45 preferably comprises anadjustable arm, one end of which moveably couples the track 43 (so as tomove therealong) with an angle that may be adjustable yet that may befixed (e.g., once adjusted) so as to remain constant between positions Aand B. Both the position of the track 43 (α, β) and the position of thesubstrate cart 45 relative to the track 43 may be easily adjustable soas to facilitate interfacing of various wafer handlers within afabrication system.

[0043] Referring again to FIG. 3A, an optional wetting system 47comprising a fluid collector 49, a splash back 51 which extends upwardlyfrom the backside of the fluid collector 49, and one or more nozzles 53which are mounted on the splash back 51 at a position and angle so as towet both surfaces of the substrate S. For example, a spray bar 55 ispositioned slightly above and, to enable wafer exchange from overhead,slightly in front of or in back of the substrate S, extends a lengthequal to the diameter of the substrate S, and has a set of nozzles 53 aangled to direct a uniform line of fluid to the backsurface of thesubstrate S, and a set of nozzles 53 b angled to direct a uniform lineof fluid to the frontside of the substrate S. Either set of nozzles 53a, 53 b may be replaced with a linear or squall type nozzle that outputsa line of fluid. The nozzles 53 a, 53 b are coupled to a fluid source56. A fluid outlet 57 is coupled to the bottom of the fluid collector 49to drain or pump fluid therefrom.

[0044] Referring to FIGS. 5A-D, the substrate cart 45 comprises two siderollers 59 a, 59 b, and a bottom roller 59 c. Each of the rollers has acentral notch or groove 61 (FIG. 5A), having a side wall angle (e.g., of45°) such that only the edge of the substrate S contacts the rollers 59a-c. The notches thus reduce damage to the front or back wafer surfaces.The rollers 59 a-c are positioned a sufficient distance apart so as tohold the substrate S in a fixed position and to prevent substratewobble.

[0045] In one aspect of the invention, in order to achieve orientationof a substrate S having a flat f (FIG. 5), the bottom roller 59 c ismotorized, and is therefore coupled to a motor 63 which may be remotelylocated or may be mounted on the backside of the substrate cart 45. Theside rollers 59 a, 59 b are configured to roll freely, and are notmotorized. The side rollers 59 a, 59 b are positioned a sufficientdistance apart so as to support the substrate S such that the flat fdoes not contact the bottom roller 59 c when the substrate S issupported by the side rollers 59 a, 59 b (FIG. 5C).

[0046] In operation, the substrate cart 45 travels along the track 43 toassume the transfer position (at location A), shown in phantom in FIG.4, and the wafer handler 48 travels along the track 50 carrying asubstrate S to position A. The wafer handler 48 places the substrate Sin the substrate cart 45 and the substrate cart 45 begins to travel upthe track 43 toward the load position (location B). In this example,while the substrate cart 45 is traveling along the track 43 fluid fromthe nozzles 53 a, 53 b prevents the substrate S from drying. The fluidruns off the substrate S into the fluid collector 49. The splash back 51prevents fluid from splashing or otherwise exiting the vicinity of thecleaning system 11. Any fluid which enters the substrate cart 45 drainstherefrom via holes (not shown) to the fluid collector 49. Fluidcollects in the fluid collector 49 and is drained therefrom via thefluid outlet 57. Because the substrate preferably is rotating (asdescribed below), the nozzles 53 a, 53 b may be positioned on the side,bottom, etc. Alternatively, the nozzles may be stationarily positionedat the transfer location, the load location or anywhere therebetween.

[0047] In one aspect, while the substrate cart 45 is traveling along thetrack 43 toward the load position (location B), the bottom roller 59 crotates, causing the substrate S to rotate therewith. The side rollers59 a, 59 b roll passively due to their contact with the rotatingsubstrate S. As soon as the flat f reaches the bottom roller 59 c, (FIG.5C) the bottom roller 59 c no longer has sufficient frictional contactwith the substrate S to rotate the substrate S. By the time thesubstrate cart 45 reaches the load position (location B), the substrateS will have been rotated via the bottom roller 59 c to a position wherethe leading edge of the flat f is adjacent the bottom roller 59 c.Accordingly, the substrate handler 33 of the substrate transfermechanism 31 can grip the substrate S without risk of contacting theflat f, which may cause the substrate handler 33 to drop the substrate S(depending on the specific configuration of the substrate handler's endeffectors). Thereafter, the nozzles 53 a, 53 b turn off and thesubstrate handler 33 grips the substrate S, the substrate transfermechanism 31 elevates and indexes forward to position the substrate Sabove the first cleaning module 15, as previously described. As soon asthe substrate S is lifted from the substrate cart 45, the substrate cart45 may begin traveling along the track 43 toward the transfer position(location A).

[0048] An alternative embodiment for orienting the substrate S is shownin FIGS. 6A and 6B. In this embodiment, the side rollers 59 a, 59 b arecoupled to the motor 63, and a sensor, generally represented by thenumber 65 in FIGS. 6A-B, is coupled to the bottom roller 59 c formeasuring the velocity of rotation thereof. The sensor 65 may be anincremental encoder (e.g., a magnetic or optical tachometer formeasuring velocity of rotation) that is capable of generating pulsefrequencies proportional to roller speed.

[0049] In operation, when the side rollers 59 a, 59 b rotate, thesubstrate S rotates therewith. The friction between the rotatingsubstrate S and the bottom roller 59 c causes the bottom roller 59 c torotate. The bottom roller 59 c may be damped, such that as soon as theflat f reaches the bottom roller 59 c and the bottom roller 59 c loosescontact with the edge of the wafer, the bottom roller stops rotating.Accordingly the sensor 65 sends a signal to a controller C. Thereafter,the controller C can signal the motor 63 to cease rotation of the siderollers 59 a, 59 c in which case the substrate will be in a knownposition with the leading edge of the flat f adjacent the bottom roller59 c. Alternatively the controller may position the flat f in any otherdesired location by rotating the rollers at a known speed for anappropriate period of time, provided the rollers are designed to avoidsubstrate slippage.

[0050] In addition to flat finding, the “orienter” of FIGS. 6A and 6Bcan be used to monitor the rotation of a substrate, whether flatted ornot. When employed for rotation monitoring, any of the supportingrollers may be coupled to rotate passively with the wafer, and may havethe sensor 65 coupled thereto.

[0051] A further embodiment for orienting the substrate S, or formonitoring the rotation thereof, is shown in FIGS. 7A-C. This embodimentis particularly well suited for use within a scrubber, and is thereforeshown within the first scrubber 17. A through-beam sensor comprising abeam emitter 71 (e.g., an optical emitter) and a receiver 73 (e.g., aphoto diode) are mounted across from each other on the front and backsurfaces, respectively, of the scrubber chamber 75. The emitter 71 andthe receiver 73 are positioned at an elevation where the beam emittedfrom the emitter 71 strikes the surface of the substrate S, near itsedge, and is therefore prevented from reaching the receiver 73 unlessthe flat f is in the region between the emitter 71 and the receiver 73,as shown in FIGS. 7B and 7C. Like the embodiments of FIGS. 5A-6B, theemitter 71 and the receiver 73 are coupled to a controller C whichprocesses the information received therefrom.

[0052] The inventive orienting mechanisms of FIGS. 5A-7C are applicableon their own (e.g., outside the cart 45) as well as within any rollerbased system which rotates a single substrate. Exemplary verticallyoriented systems include but are not limited to megasonic tanks, andscrubbers such as those previously incorporated by reference. Similarly,the inventive orienters/rotation monitors described herein are equallyapplicable to any vertically or horizontally oriented system whichrotates a single substrate via a plurality of edge rollers, e.g.,scrubbers (with roller brushes or scanning disk brushes, etc.)spin-rinse-dryers, edge cleaners, etc.

[0053]FIG. 8 is a schematic front elevational view of a substratesupport 77 that is particularly advantageous for rotating flattedsubstrates. The inventive cleaning system 11 may employ the substratesupport 77 within any module that requires rotation. The substratesupport 77, however, may be used within any apparatus that rotates aflatted wafer, and is not limited to use within the cleaning apparatusesdisclosed or incorporated herein.

[0054] The inventive substrate support 77 comprises four rollers 79 a-d.The two bottom rollers 79 b, 79 c are spaced by a distance equal to thelength of the flat f, of the substrate S positioned on the substratesupport 77 (e.g., roller 79 b and 79 c may each be positioned 29-29½°from normal). The remaining two rollers 79 a, 79 d may be positioned atany location so long as they contact the edge of the substrate S. One ormore of the rollers 77 a-d is coupled to a motor (not shown), and theremaining rollers (if any) are adapted to roll freely when the substrateS rotates.

[0055] In operation, the motorized roller(s) are energized and thesubstrate S begins to rotate. As the substrate S rotates at least threeof the four rollers 79 a-d maintain contact with the substrate S,despite the instantaneous position of the flat f. When at least rollers79 a and 79 d are both motorized, the substrate S will rotate. However,the substrate S will rotate more smoothly, and substrate/roller slippagemay be completely avoided if all four rollers 79 a-d are motorized.Accordingly, this configuration is particularly desirable for use withinmegasonic cleaners (particularly tank type cleaners) or scrubbers wheresmooth continuous substrate rotation provides more uniform cleaning, yetis often difficult to achieve as the fluid employed within such cleaningapparatuses may tend to increase substrate/roller slippage.

[0056] The modularity of the inventive cleaning system allows for anynumber of configurations. Exemplary cleaning system configurations areas follows:

[0057] 1. megasonic tank, scrubber, scrubber, spin-rinse-dryer;

[0058] 2. megasonic tank, scrubber, spin-rinse-dryer;

[0059] 3. megasonic tank, megasonic tank, spin-rinse-dryer;

[0060] 4. megasonic tank, spin-rinse-dryer;

[0061] 5. scrubber, megasonic tank, scrubber, spin-rinse-dryer;

[0062] 6. scrubber, scrubber, megasonic tank, spin-rinse-dryer;

[0063] 7. scrubber, megasonic tank, spin-rinse-dryer;

[0064] 8. megasonic tank, rinsing tank, spin-rinse-dryer;

[0065] 9. megasonic tank, megasonic rinsing tank, spin-rinse-dryer;

[0066] 10. megasonic tank, rinse, megasonic, rinse, spin-se-dryer;

[0067] 11. megasonic tank, scrubber, etch bath, rinse, spin-rinse-dryer;

[0068] 12. megasonic tank, megasonic rinse, etch bath, rinse,spin-rinse-dryer;

[0069] 13. megasonic rinse, etch, rinse, spin-rinse-dryer;

[0070] 14. etch bath, scrubber, megasonic tank, spin-rinse-dryer;

[0071] 15. etch bath, rinse, megasonic tank, spin-rinse-dryer; and

[0072] 16. etch bath, megasonic tank, spin-rinse-dryer.

[0073] An exemplary etch bath chemistry is diluted hydrofluoric acid,and an exemplary cleaning solution (e.g., for use in the scrubber,megasonic tank, etc.) is SC1.

[0074] Additionally, the input module and/or the output module may beomitted and substrates may be loaded directly to the first cleaningmodule, and/or unloaded directly from the last cleaning module.Vertically oriented wafers may be loaded into the input module and/orunloaded vertically from the output module (e.g., the input module maycomprise a chamber for receiving a vertically orientated substrate andpreventing the substrate from drying via spray, submersion etc., and theoutput module may comprise a location for receiving a verticallyorientated substrate from the cleaner's wafer handler, and for allowinganother substrate handler to extract the vertical substrate). In short,any combination of vertical or horizontal load and unload modules may beemployed as may direct loading and unloading from the cleaning modules.Further, Marangoni drying may be employed within a tank module or withinthe spin-rinse-dryer 21, or in a separate Marangoni rinser and drier. Anexemplary Marangoni drying module which may replace the spin-rinse-dryer21 in the inventive cleaner is disclosed in U.S. patent application Ser.No. 09/280,118, filed Mar. 26, 1999 (AMAT No. 2894/CMP/RKK), theentirety of which is incorporated herein by this reference. AlternativeMarangoni drying systems which may replace both the spin-rinse-dryer 21and the output module are described with reference to FIGS. 9 and 10.

[0075]FIGS. 9 and 10 depict two embodiments of inventive MarangoniDryers. FIGS. 9A and 9B are a front elevational view of a firstembodiment of a first aspect of an inventive Marangoni drying module 81a showing the exterior thereof, and respectively showing a substratereceiving position and a substrate guiding position as described below.FIG. 9C is a front elevational view of the Marangoni drying module ofFIG. 9B showing the interior thereof. FIGS. 9D-F are sequential sideelevational views of the Marangoni drying module of FIGS. 9A-C useful indescribing the operation thereof.

[0076] Although the inventive Marangoni drying modules 81 a, 81 b may beadvantageously used within the cleaning system 11 (FIGS. 1A-F) as thelast module thereof, they may also be used as a stand alone unit or aspart of another cleaning system. The inventive Marangoni drying module81 a comprises a wet chamber 83, a drying chamber 85 positioned abovethe wet chamber 83, and a dry chamber 87 positioned above the dryingchamber 85. The dry chamber 87 is coupled so that it may rotate either90 or 180 degrees so as to place a dry substrate in a desired verticalor horizontal orientation as further described below.

[0077] The interior of the wet chamber 83 (FIG. 9C) comprises a pair ofsubstrate guide rails 89 a-b which are adapted so as to move between asubstrate receiving position (shown with reference to exterior view ofFIG. 9A) wherein the guide rails 89 are positioned so as not to block anincoming wafer handler (not shown), and a substrate guiding position(shown with reference to the exterior view of FIG. 9B) wherein the guiderails 89 are positioned so as to contact the edges of a substrate andthus to restrict the lateral movement thereof as the substrate is liftedfrom the wet chamber 83 to the dry chamber 87. Each of the guide rails89 a-b has a permanent magnet 91 a-b imbedded therein. A pair of guiderail actuators 93 a-b are mounted to an outside wall of the wet chamber83 (FIGS. 9A-B). A bar 95 a-b, respectively, having permanent magnets 97a-b mounted thereto, is coupled to each guide rail actuator 93 a-b. Theexterior bars 95 a-b (FIGS. 9A-B) and the interior pair of substrateguide rails 89 a-b (FIG. 9C) are positioned such that their respectivepermanent magnets 91 a-b, 97 a-b magnetically couple through the wall ofthe wet chamber 83.

[0078] The interior of the wet chamber 83 (FIG. 9C) further comprisesthree substrate supports 99 a-c, positioned to contact the lower edge ofa substrate supported thereby. Two of the substrate supports (e.g.substrate supports 99 a and 99 c) are stationary, while the remainingsubstrate support (e.g. substrate support 99 b) is movable.Specifically, the movable substrate support 99 b has a substratesupporting end 101 a, and a guide rail mounting end 101 b (shown in theschematic side view of FIGS. 9D-F). The guide rail mounting end 101 b isslidably positioned between a pair of substrate support guide rails 103a-b, which in turn are mounted to the inside wall of the wet chamber 83.The guide rail mounting end 101 b has a permanent magnet 105 (FIG. 9C)mounted thereto. Positioned along the outside wall of the wet chamber 83is a substrate vertical motion assembly 107 (FIGS. 9D-F). The substratevertical motion assembly 107 comprises a pair of rails 109 a-b whichsupport a sliding mechanism 111 (FIGS. 9A-B). The sliding mechanism 111has a permanent magnet 113 mounted thereto so as to couple through thewall of the wet chamber 83 to the magnet 105 mounted to the movablesubstrate support 99 b (FIG. 9C). The substrate vertical motion assembly107 further comprises a drive motor 114 drive motor 114, a belt drive115 coupled to the drive motor 114 and a lead screw 117 coupled so as todrive the sliding mechanism 111 along the rails 109. The movablesubstrate support 99 b also may comprise a vacuum hole 119 (FIGS. 9D-F),coupled to a vacuum line 121 (FIGS. 9C).

[0079] The wet chamber 83 also comprises an overflow weir 123 havingoutput holes 125 through which the overflow fluid is drained.Additionally, a fluid inlet 126 (FIGS. 9A-B) is provided for supplyingfluid to the wet chamber 83.

[0080] The drying region 85 is located between the top of the rinsingfluid contained in the wet chamber 83 and a bottom wall 129 a of the drychamber 87. Gas supply tubes 131 a-b (FIGS. 9A-B) are installed justabove the rinsing fluid and so as to be on both sides of a substratebeing guided by guide rails 89 a-b. Nozzles (not shown) are formed inthe gas supply tubes 131 a-b by drilling fine holes in the thin wall andforming horizontal slots beginning at each fine hole and extendingthree-quarters of the wall thickness toward the internal diameter of thetubes 131 a-b. The tubes 131 a-b can be rotated to adjust the angle ofvapor flow from the nozzles.

[0081] The dry chamber 87 comprises a plurality of walls 129 a-f whichform a sealed enclosure. Within the dry chamber 87 a second pair ofsubstrate guide rails 135 a-b are positioned to receive and guide asubstrate as it is lifted from the wet chamber 83 through the dryingregion 85 into the dry chamber 87. The second pair of substrate guiderails 135 a-b are positioned in line with the first pair of substrateguide rails 89 a-b that are mounted therebelow in, the wet chamber 83.The dry chamber 87 further comprises a vertical motion stop 137 (FIGS.9A-F) that is adapted to selectively extend and retract so as toselectively allow substrate passage or provide substrate support. Toachieve such selective extension and retraction, vertical motion stop137 may magnetically couple through a wall 129 of the dry chamber 87.The dry chamber 87 may also comprise one or more substrate supports 139(FIGS. 9C-F) positioned to support a substrate as the substrate changesorientation (e.g., changes from a vertical to a horizontal orientationas described below with reference to FIGS. 9E-F). In one aspect each ofthe second pair of substrate guide rails 135 a-b, the vertical motionstop 137, and the dry chamber substrate support 139 are coupled to adoor 141 of the dry chamber 87. Accordingly in this aspect, a substratesupported by the second pair of substrate guide rails 135 a-b, thevertical motion stop 137, and the dry chamber substrate supports 139will rotate with the door 141 as the door 141 of the dry chamber 87 isopened (as shown and described below with reference to FIGS. 9E-F).

[0082] The door 141 (FIG. 9A-B) of the dry chamber 87 is attached to thefront wall 129 b of the dry chamber 87 via a hinge 143 (FIGS. 9D-F). Thehinge 143 may be coupled to a motor or other actuator so that the door141 may be selectively opened and closed thereby. Further, the entiredry chamber 87 is rotatably coupled to the walls of the wet chamber 83via a hinge 145 (FIGS. 9D-F). The hinge 145 may be coupled to a motor orthe like so that the dry chamber 87 may be selectively rotated 180degrees from the drying position shown in FIG. 9D to the open positionshown in FIG. 9E. A rotation stop 147 (FIGS. 9D-F) may extend from arear wall of the wet chamber 83 a sufficient distance so as to stop therotation of the dry chamber 87 at a desired position (e.g. 180 degrees).Similarly, a door rotation stop 149 may extend upwardly from a baseplate 151 (FIGS. 9D-F), a sufficient distance so as to stop the rotationof the dry chamber door 141 at a desired position (e.g., as shown inFIG. 9F, a position 90 degrees from the closed position). An additionalsupport 153 (FIGS. 9D-F) may extend upwardly from the base plate 151 soas to provide additional support for the door 141 when the door 141 isin the open position as shown in FIG. 9F.

[0083] The dry chamber 87 further comprises sealing mechanisms (notshown) which ensure that the bottom wall 129 a of the dry chamber 87seals against the walls of the wet chamber 83, and ensure that the door141 seals against the front wall 129 b of the dry chamber 87. A gasinlet 155 (FIGS. 9A-C) is coupled through one of the walls 129 of thedry chamber 87 to supply gas to the dry chamber 87, so as to dilute theflow of vapor entering the dry chamber 87 from the drying region 85and/or to pressurize the dry chamber 87. Further, the bottom wall 129 aof the dry chamber 87 comprises a slot (not shown) that is slightlylonger and wider than a substrate, and has a hole that is slightlylarger than the diameter of the movable substrate support 99 b.Accordingly a substrate may be transferred from the wet chamber 83through the drying region 85 and into the dry chamber 87 via the slot(not shown), while the dry chamber 87 remains sealed to the walls of thewet chamber 83. Each moving part of the Marangoni drying system 81 a aswell as the pumps (not shown) which supply gases or fluids to theMarangoni drying system 81 a are coupled to a controller C whichcontrols the operation of the Marangoni drying system 81 a as furtherdescribed below.

[0084] In operation when a substrate S is to be loaded into theMarangoni drying system 81 a, the hinge 145 which couples the drychamber 87 to the wet chamber 83 rotates, causing the dry chamber 87 torotate therewith to an open position, as shown in FIG. 9E. When the drychamber 87 has rotated 180 degrees the dry chamber 87 contacts the drychamber rotation stop 147 and accordingly ceases rotation. When the drychamber 87 is in the open position (FIG. 9E), the wet chamber 83 is openand a substrate S may be inserted therein. To make room for an incomingsubstrate handler 157 (FIGS. 9A-B) the guide rail actuators 93 a-b movethe bars 95 a-b outwardly. As the bars 95 a-b move outwardly, thepermanent magnets 97 a-b (which are coupled to the bars 95 a-b)magnetically couple through the wall of the wet chamber 83 to thepermanent magnets 91 a-b which are mounted to the first pair ofsubstrate guide rails 89 a-b. Accordingly the substrate guide rails 89a-b also move outwardly so as to assume the substrate receiving positionshown in FIG. 9A. When the first pair of substrate guide rails 89 a-bare in the substrate receiving position and the movable substratesupport 99 b is in the lower position as shown in FIG. 9C, the substratehandler 157 lowers the substrate S into the wet chamber 83, placing thesubstrate S on the substrate supports 99 a-c. Thereafter the substratehandler 157 opens to release the substrate S and elevates to a positionabove the Marangoni drying system 81 a. The hinge 145 then rotates thedry chamber 87 180 degrees until the dry chamber 87 is again sealedagainst the walls of the wet chamber 83 in the processing position asshown in FIG. 9D.

[0085] After the substrate S is positioned on the substrate supports 99a-c, the guide rail actuators 93 a-b move inwardly causing the firstpair of substrate guide rails 89 a-b to assume the substrate guidingposition shown in FIG. 9B. To elevate the substrate S the drive motor114 is activated and motion therefrom is transferred through the beltdrive 115 to the lead screw 117. The motion of the lead screw 117 causesthe sliding mechanism 111 to slide upwardly along the rails 109 mountedto the outside of the wet chamber 83. The permanent magnet 113 mountedto the sliding mechanism 111 couples through the wall of the wet chamber83 to the magnet 105 mounted to the movable substrate support 99 b.Accordingly as the sliding mechanism 111 moves upwardly, so does themovable substrate support 99 b and, consequently, the substrate Spositioned thereon.

[0086] As the upper portion of the substrate S enters the drying region85 the upper portion of the substrate S leaves the pair of substrateguide rails 89 a-b and is sprayed with vapors (e.g., IPA vapors) fromthe nozzles 133. The vapors mix with the film of fluid that remains onthe surface of the substrate S as the substrate S is lifted from thefluid contained in the wet chamber 83. The vapors lower the surfacetension of the fluid film, resulting in what is known as Marangonidrying. To enhance the Marangoni drying, a second set of nozzles (notshown) may supply a rinsing fluid to the surface of the substrate S asthe substrate S is lifted from the wet chamber 83. The rinsing fluidnozzles (not shown) and the set of vapor nozzles 133 are positioned suchthat the vapor from the nozzles 133 mixes with the fluid film formed onthe wafer via the rinsing fluid nozzles (not shown). The specificdetails of a Marangoni drying process that employs such a set of rinsingfluid nozzles is disclosed in commonly assigned U.S. patent applicationSer. No. 09/280,118, filed Mar. 26, 1999 (AMAT No. 2894/CMP/RKK) theentire disclosure of which is incorporated herein.

[0087] After the upper portion of the substrate S passes the nozzles 133and is dried thereby, the upper portion of the substrate S enters thedry chamber 87 via the slit (not shown) in the dry chamber 87's bottomwall 129 a, and is guided by the second pair of substrate guide rails135 a-b as the substrate support 99 b continues to elevate the substrateS. After the entire surface of the substrate S passes the verticalmotion stop 137, the vertical motion stop 137 extends from the frontwall 129 b of the dry chamber 87, to position a groove formed therein,in line with the edge of the substrate S. Thereafter the movablesubstrate support 99 b lowers, and the substrate S lowers therewithuntil contacting the vertical motion stop 137. Accordingly aftercontacting the vertical motion stop 137 the substrate S is supported bythe vertical motion stop 137, by the second pair of substrate guiderails 135 a-b, and by any additional substrate supports 139 which arepositioned along the upper edge of the substrate S. As the moveablesubstrate support 99 b begins to lower, vacuum is applied to vacuum hole119 and any fluid that may be trapped against the substrate by themoveable substrate support 99 b is suctioned from the substrate surface.

[0088] After the movable substrate support 99 b lowers past the bottomwall 129 a of the dry chamber 87, the hinge 145 is activated and rotatesthe dry chamber 87 one hundred and eighty degrees until the dry chamber87 contacts the dry chamber rotation stop 147. After the dry chamber 87begins rotation, the bottom wall 129 a of the dry chamber 87 no longerseals against the wet chamber 83. Accordingly, as soon as the drychamber 87 has rotated to a position where the dry chamber 87 no longerobstructs access to the wet chamber 83, a substrate handler such as thesubstrate handler 33 of FIG. 9 may insert a new substrate within the wetchamber 83. Thereafter, because the dry chamber 87 has rotated 180degrees, the dry chamber 87's front wall 129 b, although stillvertically oriented, now faces rearwardly as shown in FIG. 9E.Thereafter the door hinge 143 is activated and rotates the door 141 fromthe vertically oriented positioned shown in FIG. 9E, wherein the door141 seals against the front wall 129 b of the dry chamber 87, to ahorizontal orientation wherein the door 141 is supported by the doorrotation stop 149 and the additional support 153. Because the secondpair of substrate guide rails 135 a-b are coupled to the door 141, thesubstrate S is also horizontally oriented as shown in FIG. 9F. Thehorizontally oriented substrate S may now be extracted from theMarangoni drying system 81 a by a horizontal substrate handler (notshown). Accordingly, the inventive Marangoni drying system 81 a, whenemployed as the last cleaning module of the cleaner (FIG. 9), mayeliminate the need for a separate output module. Alternatively, if themechanisms supporting the substrate are appropriately configured, thesubstrate may be extracted vertically from the dry chamber when the drychamber has rotated 180° to the open position (FIG. 9E).

[0089] Note that the vertical motion stop 137 and the additionalsubstrate supports 139 may advantageously be separated by a distancewhich is slightly greater than the diameter of the substrate S.Accordingly as the substrate S changes orientation the substrate S maybe transferred from supporting contact with the vertical motion stop 137(FIG. 9A) to supporting contact with the additional substrate supports139 (FIGS. 9C-F). Thereafter, provided the additional substrate supports139 are mounted to the door 141, the additional substrate supports 139rotate with the door 141 as the door 141 opens. However, because of thepositioning of the additional substrate supports 139 (e.g., below thesubstrate S when the dry chamber 87 is upside-down, and along the inneredge of the substrate S when the door 141 is in a horizontal position(FIG. 9F), the additional substrate supports 139 do not interfere with ahorizontal wafer handler's extraction of the substrate S. The inventiveMarangoni drying system 81 a of FIGS. 9A-F is particularly advantageousfor drying 200 mm substrates, although other size substrates may also bedried thereby.

[0090] An alternative embodiment of the inventive Marangoni dryingsystem 81 a is shown and described with reference to FIG. 10A, whichrespectively shows a front elevational view of an alternative Marangonidrying system 81 b. FIGS. 10B-D are sequential side sectional views ofthe Marangoni drying module of FIG. 10A, useful in describing increasedthroughput thereof. The alternative Marangoni drying system 81 b is, forthe most part, structurally and functionally identical to the Marangonidrying system 81 a of FIGS. 9A-F, accordingly only those aspects of thealternative Marangoni drying system 81 b which differ from the Marangonidrying system 81 a are described with reference to FIGS. 10A-D.Specifically, within the alternative Marangoni drying system 81 b, thesecond pair of substrate guide rails 135 a-b are mounted to the sidewalls 129 c and 129 d of the dry chamber 87. Further, the door 141 ismounted to the top wall 129 e of the dry chamber 87, and the additionalsubstrate support 139 is mounted to the door 141. The dry chamberrotation stop 147 extends to a higher elevation (than that of FIGS.9D-F), such that the dry chamber rotation stop 147 contacts the drychamber 87 when the dry chamber 87 rotates to the horizontal position asshown in FIGS. 10C-D. Accordingly, in operation, after the substrate Sis dry, and the movable substrate support 99 c has exited the drychamber 87, the dry chamber 87 rotates 90 degrees until the dry chamber87 contacts, and is supported by, the dry chamber rotation stop 147.Thereafter the door hinge 143 is activated, and rotates, carrying theadditional substrate support 139 out of contact with the substrate S.The horizontally oriented substrate S may now be extracted from theMarangoni drying system 81 b via a horizontal substrate handler (notshown).

[0091] Accordingly, the inventive Marangoni drying systems 81 a-b, whenemployed as the last cleaning module of the cleaning system 11 (FIGS.1A-F) may eliminate the need for a separate output module. Thealternative Marangoni drying system 81 b of FIGS. 10A-D is particularlyadvantageous for drying 300 mm substrates, although other sizesubstrates may also be dried thereby.

[0092] The foregoing description discloses only the preferredembodiments of the invention, modifications of the above disclosedapparatus and method which fall within the scope of the invention willbe readily apparent to those of ordinary skill in the art. For instance,each substrate handler may individually index the vertical distancebetween the transport position and the handoff position, allowing thesubstrate supports to be positioned at varying elevations, and allowingindividual substrates to receive varying processing (e.g., to pass overa given module without being processed therein). Likewise, a givenmodule may have more than one substrate support. Particularly, forexample, it may be advantageous to have two substrate supports within amegasonic tank, and to have a separate mechanism (e.g., a mechanismmagnetically coupled through the chamber walls) for moving the substratesupports, such that the desired substrate support is positioned forsubstrate placement/extraction via the substrate transfer mechanism.Accordingly, processing within the megasonic tank may be twice as longas processing within the remaining modules. In another such aspect thesame spacing may be maintained between the substrate supports ofadjacent modules (e.g., between the input module's substrate support andthe first substrate support within the megasonic tank, and between thesecond substrate support within the megasonic tank and the scrubbermodule's substrate support) and the wafer handlers which access thesubstrate supports within the megasonic tank may be motorized such thatthe grippers move horizontally so that the desired substrate support isaccessed (e.g., if the two megasonic tank substrate supports are spaceda distance N, the grippers positioned thereabove would be spaced adistance X+N). Either such configuration may be employed within any ofthe respective modules such that the substrate supports and/or thegrippers may be spaced variable distances and still achieve simultaneouswafer transfer from one module to the next.

[0093] Substrate orientation horizontal to vertical may occur outsidethe inventive cleaning system, thus the load/unload modules would notrequire rotation mechanisms. Similarly, flat finding may be performedoutside the inventive cleaning system. The specific order and number ofcleaning modules can vary, as can the relative positioning of themodules and the shape of the transfer mechanism (e.g., circular,rectangular, etc.). Finally, as used herein, a semiconductor substrateis intended to include both an unprocessed wafer and a processed waferhaving patterned or unpatterned material layers formed thereon.

[0094] Within the inventive cleaning system the plurality of modules(megasonic tank, scrubbers, dryers, input/output, etc.) may support asubstrate in a roughly vertical orientation. By supporting the disks atan angle which is not exactly 90 degrees from horizontal (i.e., roughlyvertical), the substrates are in a known position which is much easierand more repeatably obtained, than is a perfectly vertical position.Although the exact angle may vary, a range of −10 to 10 degrees fromnormal is presently preferred and 88.5 degrees is presently mostpreferred. The wafer supports (e.g., the megasonic tank, scrubber,input/output rollers, the SRD gripper fingers and the substratehandler's pocket or clamp type grippers) each define a plane which is88.5 degrees. This 88.5 degree plane is achieved by tilting each of themodules. Thus, each wafer plane is parallel to the walls of the module.Alternatively, just the supports may be tilted. Wafers are preferablylowered into each module from overhead where they are supported bygrippers that also define a tilted plane (e.g., 88.5 degrees). Thewafers are lifted and lowered with a normal (90 degree) motion, but thewafers themselves are tilted during transport.

[0095] Throughout the cleaning system the wafer is preferably tilted thesame degree and the same direction. However, the degree and direction ofthe wafer's tilt may vary from module to module if desired, in whichcase the wafer transfer robot may be configured so as to adjust thedegree and direction of the wafer tilt. In one aspect, a wafer is tiltedtoward its backside, as this orientation will provide better laminarairflow (which is generally provided from overhead) to the frontside ofthe wafer.

[0096] Accordingly, while the present invention has been disclosed inconnection with the preferred embodiments thereof, it should beunderstood that other embodiments may fall within the spirit and scopeof the invention, as defined by the following claims.

The invention claimed is:
 1. A method of automatically cleaning asemiconductor substrate within a semiconductor substrate cleaning systemcomprising: cleaning a first semiconductor substrate within a soniccleaning tank while cleaning a second semiconductor substrate within ascrubber; automatically transferring the first semiconductor substrateto the scrubber via an overhead transfer mechanism; and automaticallytransferring the second semiconductor substrate from the scrubber viathe overhead transfer mechanism.
 2. The method of claim 1 furthercomprising: receiving a semiconductor substrate in a horizontalorientation at an input module; rotating the semiconductor substrate toa vertical orientation; automatically transferring the verticallyoriented substrate to the sonic cleaning tank via the overhead transfermechanism for cleaning; automatically transferring a semiconductorsubstrate in a vertical orientation to an output module after cleaningis complete; and rotating the semiconductor substrate in the outputmodule to a horizontal orientation; wherein rotating within the inputmodule, and rotating within the output module occur while semiconductorsubstrates are cleaned within the cleaning modules; and whereintransferring semiconductor substrates from one module to another occurssimultaneously.
 3. The method of claim 1 further comprising: providingthe sonic cleaning tank having a substrate support for supporting asingle semiconductor substrate in a vertical orientation; providing thescrubber having a substrate support for supporting a singlesemiconductor substrate in a vertical orientation; coupling the tank andthe scrubber so as to position the substrate supports thereof apredetermined distance apart; and movably coupling the overhead transfermechanism above the tank and the scrubber, wherein the overhead transfermechanism comprises a plurality of substrate handlers positioned thepredetermined distance apart.
 4. A wafer cleaning system comprising acleaning module having a wafer support which defines a wafer plane whichis approximately vertical, and a wafer handler having grippers whichdefine a wafer plane which is approximately vertical, the wafer handlerbeing adapted to transfer a wafer to and from the wafer cleaning module.5. A substrate cleaning system comprising: a megasonic tank; a scrubber;and a transfer mechanism adapted to transfer a substrate between themegasonic tank and the scrubber.
 6. A method of cleaning a substratecomprising: introducing a substrate into a cleaning system megasonicallycleaning the substrate; scrubbing the substrate; and automaticallytransferring the substrate between the megasonic cleaning and scrubbing.7. A method of cleaning a substrate comprising: supporting a substratein a roughly vertical position within a first cleaning apparatuscleaning the substrate in the first cleaning apparatus, transferring thesubstrate to a second cleaning apparatus; supporting the substrate in aroughly vertical position within the second cleaning apparatus; andcleaning the substrate in the second apparatus.